This invention pertains generally to three-dimensional position indication systems and more particularly to photoelectric docking systems for remote manipulators.
Remote manipulators are frequently employed to handle a variety of end-effectors or tools. In acquiring these tools, the wrist or hand of the manipulator is brought up to the tool and carefully positioned so that a set of jaws or a clamp can complete the attachment of the tool to the arm. Similarly, when a tool is released it is often required that the arm withdraw along a precise path to prevent bumping the tool on other nearby objects. The degree of precision with which this acquisition or "docking" is accomplished is directly related to the relative stiffness of the manipulator arm and the tool acquired. That is, a set of jaws can dock with a tool with a certain amount of clearance before the jaws close. The error in position (less than the clearance) must be taken up by the deflection of the arm or the object grasped; when the jaws close, the error at the jaw/hand interface is zero. If it was not zero, one could not tell for certain the spatial relation between the jaw and the object.
In accomplishing the acquisition maneuver, the manipulator operator requires high resolution feedback to observe the jaw/tool interface; especially when high precision is required by stiff arms and rigid tool holders. Lighting conditions and the location of television cameras do not always allow adequate viewing of the operation. Furthermore, a depth preception capability can rarely be provided even where the relative positioning of tools in three dimensional space is extremely important such as in the sophisticated application described in patent application Ser. No. 806,232, filed June 13, 1977, entitled "Remote Access Manipulator".
Accordingly, a new high resolution visual feedback system is desired to assist a manipulator operator to accurately perform remote docking and undocking maneuvers.